Diving with Cancer

Whether experienced or newly qualified, all divers who have been diagnosed with cancer need to re-evaluate their fitness to dive.
 
There are more than 200 types of cancers affecting 60 different organs in the body. The term cancer covers a wide range of medical conditions associated with abnormal and rapidly growing cells. Treatments for cancer vary both in type and effectiveness, although survival rates continue to improve through earlier diagnosis and more targeted treatments. A combination of increased awareness of early presentations, improved screening and the rising average age of the diving population have led to an increase in the prevalence of cancer amongst divers. Sun exposure, HIV infection, smoking and contemporary diets also contribute to this increase.
 
Not all abnormal growths are designated as cancers. Warts, moles, osteomas (bony outgrowths in the external ear due to cold water exposure) and skin tags are all abnormal growths, however, because growth is slow and orderly, the cells resemble normal tissue and do not invade or disrupt adjacent tissues – these are called benign growths. Conversely, highly abnormal cells which are fast growing, disordered and which have the potential to spread to other parts of the body are called malignant. By convention, cancers are usually malignant growths although this is not always strictly applied. Some technically benign growths may also cause very harmful effects, such as those in the spinal cord or skull, where the confinement imposed by the bony cavities results in rapid compression effects.

How is one’s ability to dive affected by cancer?

There are many ways in which cancer may interfere with someone’s health and therefore their ability to dive safely. In general, diving fitness is determined by a diver’s ability to:

• Withstand the physical rigors of diving and the associated pressure changes;
• Have the necessary coordination, dexterity, mental faculties and maturity to function effectively in a hostile environment; and
• Meet the civil and social obligations toward their dive buddies, dive charters and training organisations.

As such, the following factors must be considered when evaluating a person’s ability to dive with a diagnosis of cancer:

• Does the site of the tumour compromise vital organs that are affected by pressure changes?
• Does the cancer affect the individual’s physical and mental capabilities to the extent that it could pose a danger to the diver, his/her buddies or the support team? The diver must be able to care for himself/herself and be able to assist others.
• Diving must not further aggravate the disease, for example by increasing the chances of infection or bleeding.
• The treatment should not compromise physical or mental capabilities to the extent that the diver or their buddies are endangered.
• The potential for possible sudden deterioration of the condition and need for urgent treatment must be considered.

Common sites for cancers and their potential effects on fitness to dive

To illustrate how these factors may affect a diver’s diving fitness in practice, the most common cancers are reviewed briefly from the perspective of dive safety:
 
Lung Cancer

The lungs are subject to significant pressure changes in diving. As such, any tumour of the lung can increase the chances of pressure damage (barotrauma) by causing obstruction of the airways and/or distortion of the tissues, with an uneven expansion of the lung resulting in the tearing of the lung and possibly arterial gas embolism.

Lung function itself may be compromised by these changes, making diving highly risky. Often, lung tumours are highly malignant and the disease progresses quickly, so the person soon becomes physically too weak to dive.

A diver with any sort of lung cancer should have a thorough diving medical before even considering further diving. 
 
Breast Cancer

Breast cancers are common and the DAN-SA hotline receives numerous calls related to breast cancer and diving. The main issue is the treatment and its side-effects. Diving should not be undertaken before the surgical wounds have healed because of the danger of introducing infection.

The chemo- and radiotherapy used to treat breast cancer can have toxic effects on the lungs and surrounding tissues, thus compromising lung function and flexibility. Some of the drugs used in the treatment of breast cancer may have a toxic effect on the heart and reduce physical reserves. Others have the potential to cause nervous system and psychiatric side-effects, which can compromise one’s ability to dive safely.

Breast implants are sometimes used after a mastectomy. Neither the saline-filled implants (neutrally buoyant) nor the silicone implants (negatively buoyant) present problems with diving.

A diving medical exam is strongly recommended for all individuals who have been diagnosed with breast cancer. This applies to experienced and entry-level divers, irrespective of the duration, treatment or status of their cancer.
 
Intestinal Cancer

Intestinal cancers are fairly common, particularly colon cancers. These tumours and their treatment do not affect the cardiopulmonary system unless the cancer spreads to the lungs. If the cancer requires removal of parts of the intestines a colostomy may be necessary, leaving the person with a stool-collecting colostomy bag attached to an opening or stoma on the wall of the abdomen. Diving is possible with such a bag, but care of the stoma is important. Donning and removal of suits and equipment should be undertaken carefully so as not to disturb the bag or cause injury. Pressure changes do not negatively affect the intestines or colostomy bag as no compressed gas is added to the gastro-intestinal system during a dive.
 
Brain Cancer

Tumours inside the skull are invariably problematic, whether malignant or benign, due to the combination of confined space for tumour expansion, the critical loss of function associated with any brain damage resulting from the tumour, and the potential for seizures associated with disturbed brain function leading to loss of consciousness and drowning. There is also the possibility that the tumour and its treatment may increase the risk of bleeding in the brain while diving. Several drugs used to treat brain cancer may also cause altered consciousness or sedation. Neurological damage and loss of nerve function due to these treatments can make the physical activities required of divers difficult. This pre-existing nerve damage can also cause confusion with decompression illness.

People with any sort of brain tumour are unlikely to be able to dive safely and should consider other forms of recreation where sudden loss of consciousness or incapacitation is less likely to have dire consequences.
 
Lymph and Blood Cancers

These cancers and their treatment usually affect the immune system, increasing susceptibility to infection. Anaemia, fainting and the compromised ability to clot and stop bleeding are also possible side-effects with cancers of the blood and lymph tissues. If in any doubt, get the opinion of a diving medical practitioner and your doctor. 

Skin Cancer

Skin cancers are common, particularly in people with light skins who have had a lot of sun exposure and frequent episodes of sunburn. Sun damage that occurred years before can show up as a cancer later in life. Watersports, like diving, can result in very high exposure to harmful sunlight with an increased risk of skin cancers. It is therefore important to limit  and protect the skin from excessive sun exposure, particularly between 11:00 and 15:00 when the sun is at its brightest and the screening effect of the atmosphere is least effective. Use sun blockers to prevent the damage that can lead to cancers and ensure that these are applied at least 30 minutes before the sun exposure starts. Those who already have sun damage or have had tumours should be extra vigilant and consider the risks and benefits.

There are four common skin cancers. The first is technically a precancerous lesion called solar keratosis. These can usually be frozen off at this stage. The lowest grade skin cancers are the basal cell cancers or rodent ulcers; they may be disfiguring, but remain localised. Next are the squamous cell cancers that may spread to local lymph glands and may require chemotherapy or radiotherapy. Lastly there are the pigmented cancers or melanomas. These are highly malignant cancers as they are resistant to treatment and regularly spread to internal organs like the brain and liver. Most develop from simple pigmented spots or moles. There are guidelines to warn people when to seek medical advice about moles in an effort to catch early melanomas that can be treated successfully with relatively small procedures. Early signs of melanoma include changes in the shape or colour of moles or, for nodular melanoma, a new lump appearing anywhere on the skin. Moles that undergo malignant transformation may be prone to itching, ulceration or bleeding. The warning signs of melanoma can be summarised by the “ABCDE” mnemonic:

• Asymmetry: The mole is no longer round but has become oddly shaped;
• Borders: The borders around the mole have become irregular or scalloped;
• Colour: The colour of the mole is no longer a single shade of brown or black, but it has areas of significantly deeper or lighter coloration;
• Diameter: The mole is greater than 6 mm in diameter, which is about the size of a pencil eraser; and
• Evolving over time: The mole changes in size over time.

Nodular melanoma does not follow this progression, therefore new lumps appearing with the following features should prompt urgent medical attention:

• Elevated surfaces
• Firmness to the touch
• Rapid growth

Note that tumours of the face and lips that have required extensive removal could result in disfiguration which can cause problems with the fit of masks and regulator mouth pieces.

Bone, Liver, Pancreas and Kidney Cancers

Usually cancers in these organs are extensive and debilitating, resulting in fatigue, nausea, loss of weight and reduced energy levels, making it unlikely for such individuals to pursue diving as a sport. The ability to dive would have to be individually assessed by one’s doctor in consultation with a diving doctor.
 
Prostate and Genital Cancer

This type of cancer does not pose a specific problem to diving, but the extent of treatment, healing of wounds, general condition and level of fitness following the illness and its treatment are important considerations to keep in mind when starting or returning to diving.
 
General Well-Being

The emotional effects of the diagnosis and treatment of cancer can make a person feel hopeless and depressed. A cancer patient’s physical strength can take a long time to recover after chemo- or radiotherapy. Issues stemming from these effects are extremely important to address before one can dive safely.

Apart from the specific effects on the lungs and heart, as mentioned earlier, chemotherapy has side-effects like nausea and vomiting. The effect on the body in general can make the person feel weak and low on energy. Diving is not advisable in these circumstances.

When intravenous chemotherapy is administered over a longer period of time, ports are often placed underneath the skin to allow easier access. These ports themselves present no problem in diving.
 
Exercise, Cancer and Diving

The American Institute of Cancer states that staying fit, such as with scuba diving, helps to prevent cancer.
 
Physical activity helps lower blood pressure, increases bone density, regulates cholesterol, controls blood sugar, improves mood, increases brain function and improves circulation and fitness. Because of these effects, physical activity can help lower the chances of cancer, heart disease, stroke, osteoporosis, diabetes, depression, dementia and arthritis.
 
Moderate exercise during chemotherapy can be advantageous. Research by DAN America has shown a positive effect in continuing scuba diving with breast, prostate, and head and neck cancers.
 
Medical Examination for Fitness to Dive After or with Cancer

As stated previously, it is important to have an appropriate medical examination to assess fitness to dive if you have or have had any cancer that is either untreated or for which you received major surgery, radiation or chemotherapy. This would apply whether you want to start diving or whether you are an experienced diver or dive leader. It is important that the dive doctor who does the assessment has access to information including an accurate medical diagnosis, the treatment given and the extent of the disease or tissue damage remaining.
 
Contact the DAN-SA hotline on 0800 020 111 or visit the DAN-SA website at www.dansa.org for more information on diving with cancer